Fuel injection apparatus



Oct. 13, 1953 R. LEE 2,655,140

FUEL INJECTION APPARATUS Filed Dec. 1, 1947 2 Sheets-Sheet l 4038.37 25 4a INVENTOR if ROYAL E5 \&\\ Zs\\"\: we

38 4O .57 TTORNEY Oct. 13,1953 LEE 2,655,140

FUEL INJECTION APPARATUS Filed D60. 1, 1947 2 Sheets-Sheet 2 7 62 5 3/ 4 w 1) )W3PH ME y 1 v T N a V M m A l v A m A N )AL A R Patented Oct. 13, 1953 UNITED STATES PATENTOFFICE FUEL INJECTION APPARATUS Royal Lee, Elm Grove, Wis.

Application December 1, 1947, Serial No. 788,991

The present invention relates to fuel injection apparatus adapted for use with internal combustion engines.

An object of the invention is to provide improved fuel injection apparatus which shall permit close regulation of the fuel delivery and facilitate combustion of the fuel.

Another object is to provide a combined fuel injector and igniter which is applicable to combustion chambers generally and is capable of use on low-compression engines.

Still another object is to provide a fuel injector having improved means for effecting a relatively quick injection stroke.

A further object is to provide an improved hydraulic control for the injector.

A still further object is to provide for accurate control of a plurality of fuel injectors for a multicylinder engine.

The invention further consists in the several features hereinafter described and claimed.

In the accompanying drawings, illustrating certain embodiments of the invention,

Fig. 1 is an elevational view of a fuel injection apparatus of the invention applied to an internal combustion engine, parts being shown in section;

Fig. 2 is a side view of the engine with a pair of fuel injectors thereon;

Fig. 3 is a sectional elevational view of one of the injectors, taken generally on the line 3-3 of Fig. 2, a plunger of the injector being shown in retracted position;

Fig. 4 is an elevational view of the injector, parts being shown in section on the line 4-4 of Fig. 1, the injector plunger being shown in retracted position;

Fig. 5 is a top view of the injector, parts being shown in section;

Fig. 6 is a fragmentary detail view of parts of the injector body and plunger;

Fig. 7 is a detail view of an injector clamp;

Fig. 8 is a fragmentary sectional detail view of a modified form of injector body or casing;

Fig. 9 is an elevational view of a hydraulic actuator or pump for the fuel injector, parts being shown in section;

Fig. 10 is a sectional elevational view of the pump, taken generally on the line HJ-lll of Fig. 9;

Fig. 11 is a sectional elevational view of the pump, taken in a plane at right angles to the plane of Fig. 10, and

Fig. 12 is a transverse sectional view of the pump, taken on the line I2l2 of Fig. 10.

In the drawings, l5 designates an engine cylinder block having vertical cylinders l6, one being 8 Claims. (Cl. 12333) 2 shown in Fig. 1, eachprovided with apiston IT. A cylinder head I 8 is secured to the block and forms therewith at each cylinder a combustion chamber 19. The engine has the usual intake and exhaust valves or ports, not shown, for each cylinder.

The fuel injection apparatus of the invention comprises injectors 20 and pumps 2!, there being an injector and pump for each cylinder.' Each pump serves to control the operation of the associated injector and also suppliesliquid fuel to the injector, as hereinafter described.

Each injector 20 comprises a body or casing 22 having a reduced, shouldered, cylindrical lower end portion 23 which extends into a shouldered bore 24 formed through the cylinder head and is seated in the bore, there beingan annular space 25 between the lower end of the body and the lower end of the cylinder head bore. The injector body is detachably secured to the cylinder head in any suitable manner, as by a clamping plate or hold-down 26 secured to the cylinder head by a screw 21, the plate having a forked end 28 to engage in a circumferential groove 29 in the body, and an opposite downturned end 33 which bears on the cylinder head. The screw passes through a notch 3| formed in the clamping plate, and the screw head bears on a washer 32. The injector body has formed therethrough a vertical, cylindrical opening comprising upper and lower coaxial bores 33 and 34, the upper bore being of larger diameter than the lower bore. The upper end of the bore 33 is closed by a cover 35 secured to the body by screws 36, Fig. 4., and the lower end of the bore 34 is closed by a nozzle member in the form of a cap or plug 31 screwed onto the lower end of the injector body. The nozzle member has a small diameter central nozzle opening 38 which at its inner end communicates with a conical recess 39 and at its outer end communicates with a downwardly diverging conical recess 40. The lower side walls of the injector body have a number of radial bores or ports 4| through which air may freely enter into a chamber 42 in the lower end of the injector body bore 34 during the compression stroke of the engine piston. A tubular injector plunger 43 has a close slidable fit in the bore 34 to form therewith the chamber 42, and has a conically formed closed lower end 44 which is 1 adapted to fit in the nozzle cap recess 39 when the plunger is at the lower end of its pumping or injection stroke. The plunger is open at the top and has an annular out-turned top flange 45 which has a close slidable fit in the bore. 33. An

annular chamber 46 is formed between the plunger and the bore 33 and is adapted to receive liquid fuel under pressure to lift the plunger, as hereinafter described. A fuel conduit 41 of very small cross-sectional area, such as a shallow skewed groove formed along the bore 34, extends between the bore 33 and a point above the level of the air ports 4|, the lower end of the groove forming a fuel metering port 48 variably exposed by the plunger at the upper end of its stroke. The plunger is urged downwardly on its pumping or injection stroke by a strong compressed coiled spring 49 which is housed in the plunger and bears at its upper end against the'bottom of the cover 35. The upward or retracting travel of the plunger is adjustably limited by a vertical stop rod 50 which extends axially in the tubular plunger and is slidably guided in a vertical bore 5| in the cover. A top opening 52 in the cover permits insertion of the stop rod and is closed by a plug 53. The upper end of the stop rod has a head 54 which bears against an eccentric 55 formed on a, horizontal shaft 56 journalled in the cover, a light coiled spring 51 urging the stop rod upwardly against the eccentric. Angular adjustment of the shaft determines the upper limit of plunger travel and thus serves to control the exposure, by the lower end of the lifted plunger, of the fuel metering port 48' at the lower end of the fuel groove 41. The outer end of the shaft 56 carries a lever 58 which is suitably actuated, as by a governor rod 59, Fig. 2. In the case of a multi-cylinder engine, the levers 58 of the several injectors are connected for simultaneous movement by rods 60, Fig. 2. The injector shafts, however, are individually adjustable, as by providing turnbuckles 6| on the rods 60, or by shifting the levers on the shafts 56, so as to provide uniform fuel injection by the several injectors.

Liquid fuel is admitted to the injector body chamber 46 through a tube 62 which is mounted in a coupling block 63 secured to a side of the injector body by screws 64. Any upward leakage past the plunger flange 45 flows through an opening 65 in the cover 35 and out through a tube 66 which is mounted in a coupling block 61 secured to the cover by screws 88. The tubes 62 and 66 are connected to the pump M as hereinafter described.

The modified form of plunger body shown in Fig. 8 has a nozzle cap or plug 31' which is screw-threaded into the lower end 23 of the plunger body 22'. The construction is otherwise similar to that of Fig. 3.

Each pump 2I comprises a body 69 which is rigidly secured to the engine, as by an engine bracket 10 engaging lugs H on the pump body and secured thereto by bolts 12. The pump body has a vertical bore 13 in which a plunger 14 with a tubular upper portion has a close slidable fit. The lower end of the pump body has an enlarged bore 15 receiving an annular seal 16 through which the plunger slidably passes, and is closed by a bottom cover plate 11 forming a spring seat. The lower end of the plunger 14 is screw-threaded into an extension member 18 which has a peripheral flange 19 at its lower end. A compressed coiled spring 80 surrounds the extension memher and bears against the cover plate 11 and the flange 19 for urging the plunger downwardly. The extension member has a downwardly opening axial socket 81, Fig. 10, into which extends the rounded upper end of a push rod 82 by which the plunger is urged upwardly against the action of the spring 80. The push rod is suitably actuated, as by a rotary cam shaft 83, Fig. 1, driven by the engine and engaging a slidably mounted tappet 84. To limit the lifting pressure a strong compressed pressure-relieving spring surrounds the lower end of the push rod and is confined between a collar 86 on the rod and the tappet, the spring being confined by a screw 81 on the lower end of the push rod, and the rod being slidable in the tappet.

The upper end of the pump body bore 13 is closed by a screw plug 88, and a top cover member 89 is held on the pump body by a screw 90 threaded into the plug. The tubular plunger 14 has an intermediate annular channel 91 and a number of radial openings 92 extending through the plunger to provide free communication between the channel and the interior of the plunger. At the lower end of the plunger stroke, as seen in Fig. 11, the plunger channel 9| is located in an annular chamber 93 formed in the plunger body, and at the upper end of the plunger travel, as seen in Fig. 10, the channel communicates with an upper chamber 94 formed in the body. Between the chambers 93 and 9:4 is an inwardly projecting flange 95 in which the plunger slidably fits, the flange being narrower than the plunger channel 9|. Vertical vent openings 93 extend between the upper chamber 94 and the enlarged bottom bore 15, Fig. 11.

Liquid fuel is supplied to the pump body through a tube 91 which is mounted in a coupling block 99 secured to a side of the pump body by screws 99. The coupling block has a conical valve seat I90 against which bears. a cup-shaped check valve member IOI urged against the vent by a coiled spring I02. The check valve member is slidably mounted in a guide sleeve I03 and has exterior channels I04 to pass the fuel when the check valve is open. The pump body has an opening I05 providing communication between the chamber 93 and the fuel intake. At the opposite side of the pump body is attached a coupling block I06 secured to the pump body by screws I01. The tube 62, leading to the injector, terminates in the coupling block I06 and communicates with the pump body chamber 93. The upper chamber 94 of the pump body communicates with the tube 66 leading from the injector body and with another tube I08 which forms a return to a fuel supply tank, not shown. The tubes 66 and 108 terminate in respective coupling blocks I09 and H0 which are secured to opposite sides of the pump body by screws III.

In the operation of the apparatus, liquid fuel is supplied under pressure to the pump 2 I through the tube 91, flowing past the check valve IM and entering the chamber 93 in the pump body 69. The fuel also flows from the chamber 93 through the tube 62 to the chamber 49 in the injector body 22, but this pressure is insufllcient to overcome the pressure of the injector spring 49. In the cycle of operation, preferably during the compression stroke of the engine, the pump plunger 14 is gradually raised by the camshaft 83, causing fuel to be displaced at the open upper end of this plunger and forcing it from the interior of the plunger into the chamber 93 by way of the radial plunger openings 92. This pressure closes the check valve IM and forces the fuel through the tube 62 and into the annular injector chamber 46 to raise the injector plunger 43 to its stopped position, Fig. 3, against the pressure of the spring 49. At this point a limited amount of liquid fuel is forced downwardly along the fuel groove 41 to the metering port 48 and into the chamber 42 below the injector plunger, which latter chamber has received compressed air from the engine cylinder through the openings or ports 4| during the compression stroke of the engine piston. As the pump plunger [4 approaches the uppermost position seen in Fig. 10, the leading edge of the circumferential channel 9| of the plunger passes the body flange 95, thus suddenly relieving the fuel pressure in the pump chamber 93 and injector chamber 46, whereupon the injector spring 49 quickly drives the injector plunger 43 downwardly, the fuel in the annular injector chamber 46 flowing backward through the tube 62 and into the pump chamber 93 from which it flows upwardly through the bore in the flange 95 and into the upper pump chamber 94. During its quick downward stroke the injector plunger 43 first closes in succession the fuel metering port 48 and the air-admission ports 4| and then highly compresses the air in the chamber 42, forcing the air, together with fuel deposited in this chamber, through the nozzle opening 38 and into the combustion chamber of the engine. The high compression of the air in the injector chamber 42 increases the air temperature to a high value which is sufficient to ignite the fuel-air mixture when it blows out through the nozzle opening 33. In some instances, combustion may occur within the chamber 42. The fuel-air mixture sprayed under high pressure from the nozzle is diluted with the compressed air in the engine combustion chamber I9 and combustion occurs, driving the engine piston downwardly on a power stroke. The injection is timed to occur when the piston is at or near top dead center. Thereafter, the pump push rod 82 descends, and the spring 80 moves the pump plunger 14, downwardly to the position shown in Fig. 11, after which the cycle of operation is repeated. During operation, any upward leakage of fuel past the injector plunger flange 45 flows through the tube 66 to the upper chamber 94 of the fuel pump. For a light engine load the eccentric shaft 56 of the injector is turned by the lever 58 to depress the stop rod 56, thus limiting the upward travel of the injector plunger 43 and only slightly exposing the fuel port 48. In some instances the fuel metering port 48 may be completely closed by the elevated plunger 43, in which event a slight seepage of fuel along the plunger will supply a sufficient amount of fuel for idling. If the pump plunger 14 on its upward travel should encounter excessive resistance to movement before reaching the spilling position, the spring 85 on the push rod will yield and thus avoid damage to the mechanism. Pressure relief may also be obtained in other ways, as by expansion of the tube 62, or by use of a pressure relief valve, not shown. The crosssectional area of the annular injector chamber 46 is preferably small so that only a small quantity of liquid will oscillate through the tube 62 during the injector operation, thus reducing inertia effects during the quick descent of the injector plunger 43. At intervals the stop rod 50 is free from the pressure of the injector plunger 43, thus facilitating turning of the adjusting shaft 56 by the governor.

Since ignition is effected by the pressure developed by the injector, the apparatus is particularly adapted for use on low-compression engines, such as engines designed for operation on gasoline, although the apparatus may also be used on high-compression engines and on sparkignition engines.

The injector and pump are here shown to be separate units, but, if desired, they may be combined in a single structure.

When the engine stops, the injector plunger 43 will gradually descend to its lowermost position under the pressure of the spring 49, shutting off any flow of fuel into the chamber 42 and thus permitting the engine to be quickly restarted.

What I claim as new and desire to secure by Letters Patent is:

1. Fuel injection apparatus, comprising an injector body having a bore with an injector section and a retractor section, an injector plunger having a pumping portion fitting in said injector bore section and forming therewith a pumping chamber, and said plunger having another portion fitting in said retractor bore section, and spring means for urging said plunger on an injection stroke, there being an annular chamber formed between the said plunger and the retractor bore section, adapted to receive liquid under pressure for retracting said'plunger.

2. Fuel injection apparatus, comprising an injector body having a stepped bore with an injector bore section and a larger-diameter retractor bore section, a reciprocable injector plunger having a pumping portion fitting in said injector bore section and forming therewith a pumping chamber, and said plunger'having a larger-diameter portion fitting in said retractor bore section, and spring means for urging said plunger on an inj ection stroke, there being an annular chamber formed between said plunger and the retractor bore section, said chamber being closed at one end by the larger-diameter portion of said plunger and adapted to receive liquid under pressure for retracting said plunger.

3. A fuel injector for an engine combustion chamber, comprising a body having a bore with an air-compression chamber and a discharge opening and having a side wall fuel-admission port and air-admission port, said air-admission port adapted to communicate with said engine combustion chamber, a plunger reciprocable in said bore on injection and retraction strokes and having a pumping portion, said plunger exposing said ports on its retraction stroke and closing said ports on its injection stroke, and actuating means for said plunger.

4. A fuel injector for an engine combustion chamber, comprising a body having a bore therein with an air-compression chamber and a discharge opening and having an air-admission port communicating laterally with said bore and adapted to communicate with the engine combustion chamber, fuel-admission means for said aircompression chamber including a side wall port in said bore, a plunger reciprocable in said bore on injection and retraction strokes and having a pumping portion, said plunger on its injection stroke closing said fuel-admission port and air-admission port, and means for reciprocating said plunger.

5. A fuel injector comprising a body having a bore with a discharge opening adapted to communicate with an engine combustion chamber, an injector plunger reciprocable in said bore on injection and retraction strokes and having a pumping portion forming with said bore an aircompression chamber, said bore having a side wall air-admission port adapted to communicate with the engine combustion chamber, spring means for impelling said plunger on its injection stroke, retracting means for said plunger, adjustable stop means for limiting the movement of -7 said plunger on its retraction stroke, and fuel admission means for said air-compression chamber including a side wall fuel-admission port in said bore controlled by said plunger at the end portion of its retracting stroke.

6. A fuel injector comprising a body having a bore with a discharge opening adapted to communicate with an engine combustion chamber, an injector plunger reciprocable in said bore on injection and retraction strokes and having a pumping portion forming with, said bore an aircompression chamber, spring means for impelling said plunger on its injection stroke, retracting means for said plunger, adjustable stop means for limiting the movement of said plunger on its retracting stroke including a shiftable stop memher and a rotatable adjusting member for said stop member, and fuel-admission means for said air-compression chamber including a side wall fuel-admission port in said chamber having its exposure controlled by said plunger at the end portion of its adjustable retraction stroke to vary the quantity of fuel admitted to said chamher.

7. Fuel injection apparatus, comprising an injector having a cylinder with an apertured discharge chamber, a plunger reciprocable in said cylinder on injection and retraction strokes, said plunger having a pumping portion forming a wall of said discharge chamber, spring means urging said plunger on its injection stroke, and fluidpressure means distinct from said chamber for retracting said plunger against the pressure of said spring means, said discharge chamber having a fluid-admission port in a side wall of said cylinder opened and closed by the pumping portion of said plunger.

8. Fuel injection apparatus, comprising an injector having a hydraulically retracted plunger reciprocable on injection and retraction strokes and having a pumping portion, said injector having an apertured discharge chamber including a cylinder bore in which said plunger is slidable, spring means for moving said plunger on its injection stroke, fuel-metering means including a side wall fuel-admission valve port in said bore uncovered by said plunger at the end portion of its retraction stroke and closed by said plunger during its injection stroke, and adjustable means for limiting the retraction stroke of said plunger to vary the exposure of said fuel-admission port by said plunger.

ROYAL LEE.

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